The present invention relates to the formation of coated surfaces which may be used in semiconductor processing.
In semiconductor material processing facilities, plasma processing chambers are often used, for example, for etching and deposition. The walls of these chambers, as well as liners, process kits, and dielectric windows, are often exposed to corrosive and erosive process gases, as well as plasma. Therefore, plasma chambers, typically composed of aluminum, are sometimes coated with protective layers to increase the life of the chamber.
U.S. Pat. No. 8,619,406 B2 describes a coating of is yttrium oxide (yttria, Y2O3), which has been applied directly to aluminum or with an intermediary layer of aluminum oxide. An improvement over yttria is yttria-stabilized zirconia (YSZ, ZrO2:Y2O3). It is also possible to layer either of these components with other components. For example, U.S. Pat. No. 6,942,929 describes a coating of yttrium aluminum garnet (YAG, Y3Al5O12) over aluminum. U.S. Patent Pub. No. 2008/0169588 A1 describes a coating in which there is an outer layer of yttria and an intermediate layer of YAG, above a third layer of alumina. Another example is U.S. Patent Pub. No. 2014/0295670 A1, which describes a coating of yttria over aluminum oxide, over aluminum or aluminum alloy.
Given the expense and lost time in shutting down plasma processing chambers after they wear out, there is an interest in chamber coatings that have longer lifetimes, and which may have better protection against corrosive process chemicals.